Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/06—Paper forming aids
  • D21H21/12—Defoamers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D19/00—Degasification of liquids
  • B01D19/02—Foam dispersion or prevention
  • B01D19/04—Foam dispersion or prevention by addition of chemical substances
  • B01D19/0404—Foam dispersion or prevention by addition of chemical substances characterised by the nature of the chemical substance
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/03—Non-macromolecular organic compounds
  • D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
  • D21H17/14—Carboxylic acids; Derivatives thereof

Definitions

• the present invention relates to antifoams for paper industry, based on oil-in-water emulsions, in which the oil phase accounts for from 5 to 50% by weight of the emulsion, and contains a combination of known antifoams, for example long-chain alcohols or fatty esters of C 12 -C 22 -carboxylic acids and monohydric to trihydric alcohols, with polyglyceryl esters as essential components.
• known antifoams for example long-chain alcohols or fatty esters of C 12 -C 22 -carboxylic acids and monohydric to trihydric alcohols, with polyglyceryl esters as essential components.
• U.S. Pat. No. 4,950,420 discloses antifoams for the paper industry which contain from 10 to 90% by weight of a surfactant polyether, such as polyoxyalkylated glycerol or polyalkoxylated sorbitol, and from 10 to 90% by weight of a fatty ester of a polyhydric alcohol, such as a mono-or diester of polyethylene glycol or polypropylene glycol.
• a surfactant polyether such as polyoxyalkylated glycerol or polyalkoxylated sorbitol
• a fatty ester of a polyhydric alcohol such as a mono-or diester of polyethylene glycol or polypropylene glycol.
• EP-A-0 140 812 discloses that antifoams based on oil-in-water emulsions, in which the oil phase of the emulsion contains
• emulsion accounts for from 15 to 60% by weight of the emulsion and has a mean particle size of from 0.5 to 15 ⁇ m, can be stabilized to an increase in viscosity and creaming during storage by adding from 0.05 to 0.5% by weight of a high molecular weight, water-soluble homo- or copolymer of acrylic acid, methacrylic acid, acrylamide or methacrylamide.
• JP-A-60/083559 and JP-A-61/227756 disclose the use of polyglyceryl fatty esters as antifoams in the production of foods, for example tofu. These formulations contain no fatty alcohols; the presence of alkaline earth metal salts is, however, essential. Antifoam formulations are known to be effective only for the range of applications for which they have been developed, for example in the textile industry, food industry, paper industry, surface coating industry and leather industry. Owing to this specific effectiveness, antifoams cannot be successfully transferred to, or used in, other areas.
• Antifoams based on oil-in-water emulsions which are usually used in papermaking, are known to be less effective when the temperature of the aqueous system to be defoamed increases to above 35° C. At temperatures above 50° C., an even more rapid decrease in the effectiveness of the antifoams occurs when the known oil-in-water emulsions are used. Since there is an increasing tendency to use closed water circulations in the paper mills, the result is an increase in the temperature of circulated water in papermaking, so that the effectiveness of the antifoams used to date is markedly reduced.
• EP-A-0 322 830 discloses antifoams based on oil-in-water emulsions, in which the oil phase of the emulsions contains
• oil-in-water emulsions are effective anti-foams in papermaking even at above 35° C., for example at from 50° to 60° C.
• fatty acids 12 to 36 carbon atoms.
• antifoams are used, in amounts of from 0.02 to 0.5 part by weight per 100 parts by weight of the foam-forming medium, for preventing foam in pulp cooking, the beating of paper stock, papermaking and the dispersing of pigments for papermaking. In the stated amounts, they also act as deaerators in paper stocks.
• alcohols of not less than 12 carbon atoms or mixtures of alcohols are used as component (a) of the oil-in-water emulsions.
• these are monohydric alcohols which contain up to 48 carbon atoms in the molecule.
• fatty alcohols which contain a substantially larger number of carbon atoms in the molecule may also be used as component (a).
• Components (a) are either natural or synthetic alcohols. For example, lauryl alcohol, myristyl alcohol, cetyl alcohol, palmityl alcohol, stearyl alcohol, behenyl alcohol, oleyl alcohol, ricinoleyl alcohol, linoleyl alcohol and erucyl alcohol are suitable.
• Alcohols for example mixtures of (1) alcohols of 12 to 26 carbon atoms and (2) alcohols of 28 to 48 carbon atoms, can also be used as component (a).
• the synthetic alcohols which are obtainable, for example, by the Ziegler method by oxidation of alkylaluminums, are saturated, straight-chain unbranched alcohols. Synthetic alcohols are also obtained by the oxo synthesis. As a rule, alcohol mixtures are obtained here. Distillation residues which are obtained in the preparation of the abovementioned alcohols by the oxo synthesis or by the Ziegler method can also be used as component (a) of the oil phase of the antifoam emulsions.
• Alkoxylated distillation residues which are obtained in the abovementioned processes for the preparation of higher alcohols by the oxo synthesis or by the Ziegler method are also suitable as component (a) of the oil phase of the antifoam emulsions.
• the oxyalkylated distillation residues are obtained by subjecting the distillation residues to alkoxylation with ethylene oxide or with propylene oxide or with a mixture of ethylene oxide and propylene oxide by a known method. Up to 5 ethylene oxide or propylene oxide groups undergo addition per OH group of the alcohol in the distillation residue. Preferably, 1 or 2 ethylene oxide groups undergo addition per OH group of the alcohol in the distillation residue.
• Suitable components (a) are fatty esters of alcohols of not less than 22 carbon atoms and C 1 -C 36 -carboxylic acids, for example montan waxes or carnauba waxes.
• component (a) may form the oil phase of the oil-in-water emulsions.
• the fatty esters of C 12 -C 22 -carboxylic acids with a monohydric to trihydric C 1 -C 18 -alcohol are used as component (b) of the oil phase of the antifoam emulsion.
• the fatty acids which form the basis of the esters are, for example, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid and behenic acid. Palmitic acid or stearic acid is preferably used for the preparation of the esters.
• Monohydric C 1 -C 18 -alcohols can be used for esterifying the stated carboxylic acids, for example methanol, ethanol, propanol, butanol, hexanol, decanol and stearyl alcohol, as well as dihydric alcohols, such as ethylene glycol, or trihydric alcohols, such as glycerol.
• the polyhydric alcohols may be completely or partially esterified.
• the oil phase of the emulsion may additionally be formed by a further class of water-insoluble compounds which are referred to below as component (c).
• component (c) may account for up to 50% by weight, based on components (a) and (b), of the oil phase of the antifoam emulsions. They may be added either to a mixture of components (a) and (b) or to each of the compounds stated under (a) or (b).
• Suitable components (c) are hydrocarbons having a boiling point of more than 200° C. at 1013 mbar and a pour point below 0° C., or fatty acids of 12 to 22 carbon atoms.
• Preferred hydrocarbons are liquid paraffins, such as the commercial paraffin mixtures, which are also referred to as white oil.
• Components (a) and (b) can be used in any ratio for the preparation of the antifoam emulsions. Each of these two components may be present in the antifoams either alone or as a mixture with the other. In practice, for example, mixtures of (a) and (b) which contain from 40 to 60% by weight of component (a) and from 60 to 40% by weight of component (b) have proven useful.
• the oil phase of the oil-in-water emulsions may additionally contain one or more compounds (c). However, it is essential that at least one of the abovementioned components (a) and (b) in combination with one or more compounds of the following group (d) forms the oil phase of the oil-in-water emulsions.
• the compounds (d) account for from 1 to 80, preferably from 5 to 20, % by weight of the oil phase of the oil-in-water emulsions.
• the oil phase of the antifoam emulsions necessarily contains one of the following combinations: (a) and (d), (b) and (d) and (a), (b) and (d).
• the compounds of component (c) may be used in amounts of up to 40% by weight, based on the oil phase of the oil-in-water emulsions, in the case of all three abovementioned combinations of the composition of the oil phase.
• Suitable components (d) of the oil phase are polyglyceryl esters which are obtainable by not less than 20% esterification of polyglycerol mixtures of
• the polyglycerol mixtures described above are preferably esterified with fatty acids of 16 to 30 carbon atoms.
• the degree of esterification is from 20 to 100%, preferably from 60 to 100%.
• the fatty acids which are suitable for esterifying the polyglycerol mixtures may be saturated fatty acids as well as unsaturated fatty acids, for example lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid and montanic acid.
• Ethylenically unsaturated fatty acids for example oleic acid, hexadecenoic acids, elaidic acid, eicosenoic acids and docosenoic acids, such as erucic acid or brassidic acid, and polyunsaturated acids, such as octadecenedienoic acids and octatrienoic acids, such as linoleic acid and linolenic acid and mixtures of the stated saturated and unsaturated carboxylic acids are also suitable for esterifying the polyglycerol mixtures.
• the polyglycerol mixtures are obtainable, for example, by alkaline-catalyzed condensation of glycerol at elevated temperatures (cf. for example Fette, Seifen, Anstrichstoff, 88th year, No. 3, pages 101 to 106 (1986) or DE-A 3 842 692), by reacting glycerol with epichlorohydrin in the presence of an acidic catalyst at elevated temperatures.
• the mixtures are also obtainable by mixing the pure polyglycerol components, for example diglycerol, triglycerol and tetraglycerol, with one another.
• the polyglycerol mixtures which are not less than 20% esterified are prepared by esterifying the polyglycerol mixtures with the desired fatty acid or mixture of fatty acids by a known method.
• the reaction is carried out in the presence of an acidic esterification catalyst, such as sulfuric acid, p-toluenesulfonic acid, citric acid, phosphorous acid, phosphoric acid or hypophosphorous acid, or of a basic catalyst, such as sodium methylate or potassium tertbutylate.
• an acidic esterification catalyst such as sulfuric acid, p-toluenesulfonic acid, citric acid, phosphorous acid, phosphoric acid or hypophosphorous acid
• a basic catalyst such as sodium methylate or potassium tertbutylate.
• the compounds of component (d) are present in an amount of from 1 to 80, preferably from 5 to 20, % by weight in the oil phase.
• the oil phase accounts for from 5 to 50% by weight of the oil-in-water emulsions, while the content of the aqueous phase in the emulsions is from 95 to 50% by weight, the percentages by weight summing to 100.
• the oil phase is emulsified in the aqueous phase.
• Apparatuses in which the components of the emulsion are subjected to a strong shear gradient for example dispersers, are required for this purpose.
• the emulsification of the oil phase in the aqueous phase is preferably carried out in the presence of surfactants which have an HLB value of more than 6 (for the definition of the HLB value, see W. C. Griffin, Journal of the Society of Cosmetic Chemists, 5 (1954), 249-246).
• the surfactants are oil-in-water emulsifiers or typical wetting agents.
• anionic, cationic or nonionic compounds or mixtures of these compounds which are compatible with one another, for example mixtures of anionic and nonionic or of cationic and nonionic wetting agents.
• Substances of the stated type are, for example, sodium salts or ammonium salts of higher fatty acids, such as ammonium oleate or ammonium stearate, oxyalkylated phenols, such as nonylphenol or isooctylphenol which have been reacted with ethylene oxide in a molar ratio of from 1:2 to 1:50, oxyethylated unsaturated oils, for example the reaction products of one mol of castor oil and from 30 to 40 mol of ethylene oxide or the reaction products of one mol of sperm alcohol with from 60 to 80 mol of ethylene oxide.
• Sulfated oxyethylation products of nonylphenol or octylphenol are also preferably used as emulsifiers, said products being present as the sodium or ammonium salt of the corresponding sulfuric half-ester.
• 100 parts by weight of the oil-in-water emulsions usually contain from 0.1 to 5 parts by weight of an emulsifier or of an emulsifier mixture.
• protective colloids such as high molecular weight polysaccharides and soaps, or other conventional additives, such as stabilizers, may also be used in the preparation of the oil-in-water emulsions.
• Emulsifying the oil phase in the aqueous phase gives oil-in-water emulsions which have a viscosity of from 300 to 3,000 mPa.s immediately after preparation and a mean particle size of the oil phase of less than 25 ⁇ m, preferably from 0.5 to 15 ⁇ m.
• component (d) alone or as a mixture with component (c)
• component (c) have virtually no activity as oil-in-water emulsion antifoams
• component (d) to the oil phase of antifoams which contain components (a) and/or (b) and, if required, further components in emulsified form has little or no adverse effect on the effectiveness of the resulting antifoams at relatively low temperatures, for example at room temperature, but increases the effectiveness of the antifoams to an unexpected extent in aqueous systems whose temperature is above 40° C.
• the novel oil-in-water emulsions are used in the paper industry in aqueous systems in which the formation of foam at relatively high temperatures must be prevented, for example in pulp cooking, in the beating of paper stock, in papermaking with closed water circulations in paper machines, and in the dispersing of pigments for papermaking.
• part by weight of the oil-in-water antifoam emulsion is used per 100 parts by weight of paper stock in a foam-forming medium.
• the antifoams When added to a paper stock suspension, the antifoams furthermore result in deaeration and are therefore also used as deaerators in papermaking (added to the paper stock). They are also suitable as antifoams in paper coating, where they are added to paper coating slips.
• the antifoams can also be used in the food industry, in the starch industry and in wastewater treatment plants for preventing foam. If they are added to the paper stock as a deaerator, the amounts used for this purpose are from 0.02 to 0.5 part by weight per 100 parts by weight of paper stock.
• the mean particle size of the particles of the oil phase which are emulsified in water was determined using a Coulter counter.
• the K value of the polymers was determined according to H. Fikentscher, Cellulose-Chemie, 13 (1932), 58-64 and 71-74, in aqueous solution at 25° C., at a concentration of 0.5% by weight and at a pH of 7.
• the temperature of the paper stock suspension is 30°, 40°, 50° or 60° C., the temperature being kept constant within ⁇ 1° C. during the 5 minute test.
• the effectiveness of an antifoam is represented as the percentage of residual foam.
• the percentage of residual foam (R) is calculated as ##EQU1## where S o is the foam index measured after the additon of an antifoam and S o is the foam zero value, ie. the value measured in the absence of an antifoam. In this terminology, the smaller R is the better the antifoam.
• An oil-in-water emulsion in which the oil phase accounts for 30% by weight of the emulsion and has a mean particle size of from 3 to 10 ⁇ m is prepared with the aid of a disperser.
• the oil phase consists of the following components:
• the water phase consists of:
• Components (a) to (d) are first heated to 110° C. and then added to the aqueous phase at 80° C. with dispersing.
• the oil-in-water emulsion thus obtained has a viscosity of 2650 mPa.s at 20° C. immediately after preparation.
• the effectiveness of this antifoam emulsion is tested, as described above, on a paper stock suspension. The following results are obtained for the residual foam index R in percent at each of the temperatures used for the paper stock suspension:
• An oil-in-water emulsion is prepared by the method stated in Example 1, except that component (d) is omitted and the amount of the fatty alcohol mixture of component (a) is increased to 23 parts.
• An emulsion whose viscosity immediately after preparation, at 20° C., is 540 mPa.s is obtained.
• this emulsion is tested, the following residual foam indices in percent are obtained for the temperatures of the paper stock suspension which are stated in the Table:
• the aqueous phase is brought to pH 6.5. This change leads to a substantial decrease in the viscosity of the emulsions.
• Example 2 An emulsion is prepared by the method described in Example 2, the aqueous phase of Example 1 remaining unchanged and the oil phase of the antifoam having the following composition:
• the degree of esterification is 60%.
• Example 2 An emulsion is prepared by the method described in Example 2, the aqueous phase of Example 1 remaining unchanged and the oil phase of the antifoam having the following composition:

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Dispersion Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Colloid Chemistry (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Medicinal Preparation (AREA)
• Medicines Containing Material From Animals Or Micro-Organisms (AREA)

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Citations (10)

• 1991
  • 1991-08-22 DE DE4127719A patent/DE4127719A1/de not_active Withdrawn
• 1992
  • 1992-07-16 CA CA002074054A patent/CA2074054C/en not_active Expired - Lifetime
  • 1992-08-07 EP EP92113458A patent/EP0531713B1/de not_active Expired - Lifetime
  • 1992-08-07 AT AT92113458T patent/ATE122114T1/de active
  • 1992-08-07 DE DE59202075T patent/DE59202075D1/de not_active Expired - Lifetime
  • 1992-08-07 ES ES92113458T patent/ES2071391T3/es not_active Expired - Lifetime
  • 1992-08-18 JP JP21918492A patent/JP3222209B2/ja not_active Expired - Fee Related
  • 1992-08-20 FI FI923754A patent/FI113074B/fi not_active IP Right Cessation
  • 1992-08-20 US US07/933,191 patent/US5326499A/en not_active Expired - Lifetime
  • 1992-08-21 AU AU21244/92A patent/AU648687B2/en not_active Expired

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